The proposed project is a neurobiological investigation of the structure of ascending projections of the brainstem reticular formation. Experimental neuroanatomical studies employing autoradiography, peroxidase histochemistry, and experimental degeneration techniques will be used to study the morphology of reticular efferents, as well as the projections of some of the regions (particularly medial thalamus and subthalamus) that receive direct reticular input. Although a wide variety of techniques and approaches will be employed, the results will be integrated in an attempt toward an overall understanding of the relationships of the brainstem reticular formation with the forebrain.